Fiber optic sensors are known to have a number of beneficial properties over conventional electronic sensors, such as reduction/elimination of EMI susceptibility, electrical isolation with no electrical current/power at the sensing area, insensitivity to radiation, remote readout, no wires, robust, wide temperature range, small size for high fidelity measurements, and highly manufacturable and reproducible.
Various types of fiber optic sensors are commercially available based on a white light Fabry-Perot interferometric readout concept for measuring strain, temperature, etc. Such sensors are generally made by precisely positioning and attaching segments of optical fiber in tiny glass capillary tubes.
There is still a need, however, for a lightweight, high sensitivity gauge for gap width measurement which is capable of accurately sensing position, displacement, and gap width at the micrometer level with a micro sensor, while being small enough to fit the requirements of a restricted amount of space and achieving the other benefits associated with fiber optic sensors.